/*
    * Copyright 2016 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty5.channel.unix.tests;
  
  
  import java.lang.reflect.Method;
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.net.SocketAddress;
  
  import static org.junit.jupiter.api.Assumptions.assumeTrue;
  
  public final class UnixTestUtils {
      private static final Object INET_LOOPBACK_UNAVAILABLE = new Object();
      private static volatile Object inetLoopbackCache;
  
      /**
       * The JDK method may produce IPv4 loopback addresses where {@link io.netty5.util.NetUtil#LOCALHOST} might be an
       * IPv6 addresses.
       * This difference can stress the system in different ways that are important to test.
       */
      public static SocketAddress newInetLoopbackSocketAddress() {
          Object loopback = inetLoopbackCache;
  
          if (loopback == null) {
              inetLoopbackCache = loopback = getLoopbackAddress();
          }
  
          assumeTrue(loopback != INET_LOOPBACK_UNAVAILABLE, "InetAddress.getLoopbackAddress() is not available");
          return new InetSocketAddress((InetAddress) loopback, 0);
      }
  
      private static Object getLoopbackAddress() {
          try {
              Method method = InetAddress.class.getMethod("getLoopbackAddress");
              return method.invoke(null);
          } catch (Exception ignore) {
              return INET_LOOPBACK_UNAVAILABLE;
          }
      }
  
      private UnixTestUtils() { }
  }